%I #7 Sep 02 2024 10:35:08
%S 9,9,9,9,1,9,2,9,3,9,7,0,0,1,7,5,5,9,3,2,4,2,8,2,6,5,5,3,2,0,3,2,2,8,
%T 8,4,6,9,8,3,4,9,2,8,0,3,1,7,2,7,7,0,3,1,5,3,2,3,1,9,2,8,4,1,3,6,6,5,
%U 7,0,0,1,7,0,6,5,2,6,3,1,3,2,0,9,3,3,4,8,9,7,2,3,7,7,7,7,1,0,3,7,5,5,1,9,6,3
%N Decimal expansion of Product_{k>=1} (1 - exp(-3*Pi*k)).
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/DedekindEtaFunction.html">Dedekind Eta Function</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/q-PochhammerSymbol.html">q-Pochhammer Symbol</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Dedekind_eta_function">Dedekind eta function</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Euler_function">Euler function</a>
%F Equals (5 - sqrt(3) + sqrt(2)*3^(3/4))^(1/6) * exp(Pi/8) * Gamma(1/4) / (2^(25/24) * 3^(3/8) * Pi^(3/4)).
%e 0.999919293970017559324282655320322884698349280317277031532319284136657...
%t RealDigits[(5 - Sqrt[3] + Sqrt[2]*3^(3/4))^(1/6) * E^(Pi/8) * Gamma[1/4] / (2^(25/24)*3^(3/8)*Pi^(3/4)), 10, 120][[1]]
%t RealDigits[QPochhammer[E^(-3*Pi)], 10, 120][[1]]
%o (PARI) (5 - sqrt(3) + sqrt(2)*3^(3/4))^(1/6) * exp(Pi/8) * gamma(1/4) / 2^(25/24) / 3^(3/8) / Pi^(3/4) \\ _Charles R Greathouse IV_, Sep 02 2024
%Y Cf. A292862, A292863, A259147, A259148, A259149, A259150, A259151, A292864.
%Y Cf. A292887.
%K nonn,cons
%O 0,1
%A _Vaclav Kotesovec_, Sep 26 2017